Intermodal rail volume rose 3.4% for the week ended Sept. 21 from the same week a year ago, the Association of American Railroads reported.
Traffic increased to 262,897 trailers and containers, AAR said in its weekly report.
Rail carload traffic dipped 1.5% to 288,160 year-over-year, the rail trade group said.
Six of the 10 carload commodity groups tracked by AAR posted increases, led by petroleum and petroleum products, which increased 8%. Commodities showing a decrease included grain, which fell 21.3%.
For the first 38 weeks of the year, U.S. railroads moved 9.3 million intermodal containers and trailers, up 3.7% from last year. Carload traffic dipped 1% to 10.6 million units.